A parasitic disease is an caused or transmitted by a. Many parasites do not cause diseases. Parasitic diseases can affect practically all living, including and. Some parasites like and can cause disease directly, but other organisms can cause disease by the that they produce.

Although organisms such as function as parasites, the usage of the term "parasitic disease" is usually more restricted. The three main types of organisms causing these conditions are (causing), Protozoa and helminths are usually endoparasites (usually living inside the body of the host), while ectoparasites usually live on the surface of the host.

• It is an important rickettsial infectious disease of ruminants.
• Exotic and crossbred cattle are highly susceptible.
  

• The disease is caused by Anaplasma marginale.
• The anaplasmas are intra-erythrocytic bodies.
• They can be destroyed by heating at 60˙C for 60 minutes.

• The infection spreads through ticks.
•  Besides tick, Tabanas spp., Stomoxys spp. And mosquitoes have been found to transmit the disease.
• Carrier animals like cattle and other wild ruminants play vital roles in the transmission of the disease.
• Mechanical transmission through dehorning, castration, vaccination, ear marking has been suggested.
• Transplacental transmission has been observed.

• High rise of temperature,
•  Loss of condition,
• Nasal discharge, lacrymation,
• Inappetance,
• Coughing, dry rales, moist rales,
• Rumen atony, dehydration, rough body coat, dyspnoea and muscle tremors.
• Enlargement of superficial lymphnodes,
• Grinding of teeth,
• Pale and icteric mucous membrane.

• This condition should be handled with qualified veterinary doctor.
• Strict control of insect population should be made by acaricidal spray or dips.
• Carrier animals should be isolated and disposed.
• Serological test of the herd should be made and the positive one should be brought under treatment.
• Prophylactic immunization against Anaplasmosis is done by preimunition, attenuated vaccine of ovine origin and inactivated vaccine of ovine and bovine origins.

• Theileriosis is an important disease in exotic and cross bred dairy cattle

• The species of Theileria those affect cattle are T.annulata, T.parva and T.mutans.
• T.annulata is the most extensively distributed parasite and causes tropical Theileriosis.

• The disease is mostly observed during summer and rainy seasons.
• This preponderance is attributed to higher activity of vector during this season (May to October). This is also influenced by stress due to hot and humid weathers.
• The disease is transmitted by the bite of the ticks of the genus Hyalomma.
• Erythrocytic forms of the parasite are ingested by the larval and nymphal stages of the tick along with blood, while feeding on an infected animal.
• The subsequent stages of the tick (nymph and/or adults) transmit the disease during their feeding on susceptible hosts (Transtadial transmission).
• The disease can also be transmitted mechanically by inoculation of infective blood and tissue suspension made from spleen, lymph node and liver of infected animals.

• High rise of temperature (40.5˙C to 41.5˙C).
• Enlargement of regional superficial lymph nodes.
• Anorexia, restlessness and rough coat.
• Tense eye balls along with watery lacrymation.
• Laboured respiration, serous, nasal discharge and coughing.
• Depression and petechial haemorrhages on conjunctiva.
• Declination of fever and development of anaemia with high coloured urine in later stage.
• Urticarial type skin lesions.
• Weakness, prostration and death.

Skin lesions

• Tick population should be controlled.